Tandem check valves



Nov. 29, 1955 F. T. IRGENS TANDEM CHECK VALVES Filed Feb. 2, 1952 MUWFMZJ Gttornegs United States Patent TANDEM CHECK vA-Lvns Finn T.Irgens, 'Wauwatosa, Wis., as'signor to Outboard, Marine & ManufacturingCompany, Waukegan, [1]., a corporation of Delaware Application February2,1952, Serial No. 269,649

4 Claims. (Cl. 137- 5121) This invention relates to improvements incheck valves disposed between a carburetor and an internal combustionengine, and particularly to a novel arrangement .of a plurality of checkvalves whereby the valves are physically in tandem but act .in parallel.

The object of the invention is to provide a valve structure with highvolumetric capacity, butof compact physical structure whereby space andweight limits can be .reduced while at the same time the capacity of thevalve may be increased.

In the embodiment shown a main valve is provided withan annular portarea providing one flow path for the fuel mixture, and with a centralopening to which there is coupled a tandem valve comprising a cup-shapedholder flaring from the inlet to a port area which provides anadditional flow path for the fuel mixture. In this manner the volumetriccapacity of the valve may be increased without necessitating increase inthe lateral dimensions-of the valve structure. It is broadly immaterialhow many tandem valves are mounted one upon the other, this being amatter dictated by the fuelrequirements of the engine.

In this connection, a novel arrangement of valve diaphragm, portpattern, and a diaphragm damper or backing member has been providedwhereby to improve the operation of the valve over valves heretoforeknown.

In the drawings:

Fig. 1 is a view in axial cross section through a .passage leading froma carburetor to an internal combustion engine, a tandem check valveembodying the invention being disposed in said passage.

Fig. 2 is an elevation view of the outlet side of the valve shown inFig. 1, portions being broken away.

Fig. 3 is a view of the valve shown in Fig. 1 looking in the directionof the arrow A in Fig. 1.

Fig. 4 is a plan view of two of the valves embodying the inventionmounted on a single plate.

A tandem check valve structure embodying my invention is hereindisclosed in a typical environment such as its application to a twocycle internal combustion engine of the type used in outboard motorswhere the fuel mixture from the carburetor is admitted to the crank caseportion of the engine. These valves commonly comprise check valves whichadmit fuel mixture on the intake stroke of the piston but which close toprevent escape of the mix on the power stroke of the piston. However,the valve is adapted for other uses wherever a check valve having highvolumetric capacity is needed.

As best shown in Fig. 1 the wall 10 defines a passage affordingcommunication between a carburetor chamber 11 and an engine chamber 12.Spanning the passage 10 so as to control fluid flow from chamber 11tochamber 12 is a check valve structure comprising an apertured mountingplate and partition 14 having a concave valve seat portion 13. The plate14 has its margins clamped between wall elements 10 and 10 whereby tosupport the concave seat 13 and the tandem valve to be hereinafterdescribed.

The dished or concave seat 13 is provided with an an- 2,725,075 PatentedNov. 29, 1955 ice nular series of grouped ports 15, surrounding acentral aperture which has a margin 16. The ports 15 of the concavevalve seat 13 are normally covered on the outlet, or engine chamber,side of the valve seat by a flat valve, here comprising a flexibleannular diaphragm 17, to be hereinafter described in more detail.

To the aperture margin 16 is clinched the annular flange 20 of acup-shaped member or housing 18 which flares from its inlet 20 to anintegral shoulder at 19 which is ofgreater area extent than inlet 20 andis bounded by a rim 21.

The shoulder 19 of cup 18 embraces a concave partition disk 22 which isprovided with an annular series of ports 23 surrounding a centralaperture 24. The ports 23 are normally covered on the outlet, or enginechamber, side of disk 22 with a flexible annular diaphragm valve 25,normally self biased to seat against the disk and anchored by themounting button 27.

The main diaphragm valve 17 has its inner margin 21 securely held to themain valve seat 13 by pressure of the base of the cup 18 against themargin 16 of the seat. The outer periphery of the diaphragm is free tolift under fluid pressure to mould the diaphragm about the cup, theshape of which is such that very little movement is permitted thediaphragm near its fixed central portions and progressively greatermovement is permitted toward the perimeter.

"Similarly, the button 27 has a flaring form to limit the movement ofvalve 25 in a manner tending to preclude crystallization of the valve.Button 27 desirably comprises rubber or resilient plastic. The tandemvalve is, however, desirably provided with an additional backing memberor damper 26 which is also annular, but of less radial extent thandiaphragm 25, and mounted at its inner margin between the button 27 andthe seat 22.

While the disposition of the ports of both valves is generally annular,it is preferred that the ports be arranged in groups which are angularlyspaced in patterns as best shown in Fig. 2 and Fig. 3. The unportedradial zones between groups of ports provide support for the respectivehub portionso'f'the main valve seat and tandem valve seat to which thediaphragms aforesaid are mounted.

While broadly immaterial, it has been found that a more satisfactoryvalve action is obtained by providing the respective valve diaphragrns17 and 25, as well as the backing member 26 for valve 25, with radialslots which respectively give the valves and backing member a cloverleafform. For this purpose the main diaphragm 17 is provided with radialslots 32, the tandem valve diaphragm 25 is provided with radial slots 33and the backing member 26 is provided with radial slots 34. In theembodiment illustrated the main valve seat 13 has six groups of ports15, and hence has six imperforate zones 39 spaced at 60 intervals, thediaphragm 17 having six slots 32 complementarily spaced. The tandemvalve seat, being of :iess radial extent than the main valve seat, needonly have four groups of ports 23 with four intervening spokes 31angularly spaced by The valve diaphragm 25 and backing member 26 havefour complementarily spaced slots 33 and 34. The respective slots 32, 33and 34 are aligned to overlie imperforate radial zones 36 and 31 of therespective valve seats so as not to interfere with the checking functionof the valve diaphragrns in closing the ports. Stated generally thefunction of the radial slots is to render the flexible diaphragms moreflexible and yieldable and to be more responsive to pressuredifferential at the inlet and outlet sides of the ports.

For the purpose of insuring registry of the radial slots 33 and 34 withthe spokes 31 of the tandem valve seat 22, the diaphragm 25 and backingmember 26 are keyed to the valve seat 22 in such a way that when thebutton 27 is engaged with the central aperture 24 in the valve seat 22the respective radial slots will automatically align with the spokes 31of the valve seat. While the keying arrangement is broadly immaterial ithas been found that a square aperture 24 in the valve seat inconjunction with a square shank 35 on the button 27 is more effective toproperly key the respective diaphragms to the valve seat. Accordingly,it is assured that each leaf of the cloverleaf pattern of diaphragm andbacking member will cover one group of ports.

As best shown in Fig. l the square shank 35 of button 27 has aperipheral groove 36 which is in normal engagement with the margins ofthe aperture 24 in the valve seat 22. The shaft portion 37 between thegroove 36 and the undersurface or shoulder of the button 27 issubstantially equal in dimension to the combined thickness of thediaphragm 25 and the backing member 26 so that these elements will besnugly mounted between the button and the valve seat when the groove 36is engaged with the margins 24 of the valve aperture. To provide forease of assembly the button shank 35 is provided with an extension 38shown in dotted lines in Fig. l which is normally cut off after thebutton has been wedged into position.

The arrangement shown in Fig. 4 illustrates the mounting of two of thetandem check valves upon a single plate 41. This common mount adapts thevalve assembly for use with multi-cylinder engines in which differentcylinders have different fuel cycles.

From the foregoing it will be evident that on the intake stroke of theengine piston both valve diaphragms 17 and 25 will open to admit fuelmixture to the engine in response to the higher pressure on the intakeor carburetor side of the respective ports. Upon the power stroke of thepiston, and a higher pressure on the outlet or engine side of the ports,the respective valve diaphragms 17 and 25 will close against the portedplates to prevent escape of the fuel mixture from the engine.Accordingly, the valves act in parallel. As volumetric capacity ofengines is increased and the size and weight of engine parts aredecreased it has been found that a single valve will frequently notpermit suificient fuel mixture to enter the engine on the intake stroketo permit the full power of the engine to be developed upon the powerstroke of the piston. The present tandem valve structure provides forample influx of fuel mixture to the engine Without requiring enlargementof the passage between the engine and carburetor. This improved resultis attained without departing from the preferred use of the diaphragmcheck valves illustrated. The tandem arrangement disclosed is highlyflexible as one or more tandem valves may be used as desired withoutrequiring enlargement of passageway 10.

The novel relation between the valve diaphragm 25 and backing member 26provides a stiffener for the diaphragm 25 to insure its quick return toport closing position during the power stroke of the engine. This isparticularly important after the diaphragm 25 has been in use over aperiod of time. The main valve diaphragm 17 is backed by the undersurface of the cup 18 which performs a similar backing function. Whilethe composition of the diaphragm and backing member is broadlyimmaterial for the purpose of the present invention, they should beflexible and resilient.

The respective valve diaphragms may be of thin resilient ornon-resilient metal, or of plastic or rubber, or of coated fabric.Natural and synthetic rubber compositions have been used withsatisfactory results.

I claim:

1. A valve comprising a partition element having ports arranged in anannular pattern, an annular flexible diaphragm peripherally comprising aflap valve covering said ports at one side of the element and mounted tosaid element centrally of the port pattern, and an annular backingmember of less radial extent than the diaphragm and secured to saidelement in clamping engagement with the diaphragm at its inner annularmargin and progressively divergent outwardly from said element wherebyto control diaphragm port uncovering movement, said port-s beingarranged in groups angularly spaced in said annular pattern, saidelement having intervening unported portions of said element, saiddiaphragm being radially slotted in registry with said unportedportions, said backing member comprising a cup shaped member having acentral opening and marginally connected about said opening with saidpartition element and flaring outwardly from such connection over saidelement and diaphragm in clamping engagement with the diaphragm nearsaid opening and progressively diverging from said element, in furthercombination with a second partition mounted on said flaring cup shapedmember in a position axially offset from said opening and havingmaterially greater diameter than said opening, said second partitionhaving a central opening and having ports between said opening and itsperiphery, a second flap valve diaphragm mounted on the second partitionand covering the valve ports therein, and mounting means fixed in thecentral opening of the second partition and clampingly holding saidsecond flap valve diaphragm to the second partition, the opening in thesecond partition being non-circular and the last named means having acomplementary form whereby to be keyed non-rotatively to the secondpartition, the second diaphragm valve means having a correspondingcentral opening whereby it likewise is keyed against rotation respectingthe second partition, said second partition having its ports arranged ingroups angularly spacedfrom each other and the second diaphragm valvemeans having generally radial slots positioned to lie between the groupsof ports.

2. A tandem valve organization comprising a mounting plate having adished portion and provided near the center of said portion with anopening and further having valve ports arranged in annular series aroundsaid opening, a generally annular flap valve having outer peripheralportion-s covering said ports and an inner peripheral portion proximateto said opening, a cup shaped housing having at its bottom an annularflange extending through the annular valve means and the opening of saidplate and thence radially in clamping relation to said plate, saidhousing having outwardly flaring side wall portions in clamping relationwith the inner periphery of said annular valve means and progressivelydivergent from said valve means and plate, an integral shoulder on saidhousing axially remote from said plate and overhanging the valve portsof said plate, a disc mounted on said shoulder and provided with asecond set of valve ports in annular series, a second generally annularflap valve means mounted on the disc and having outer peripheralportions covering said ports, and means connected with the disc andextending through the second flap valve means and overlying innerperipheral portions of said second flap valve means in clamping relationthereto for mounting said second flap valve means on said disc.

3. A tandem check valve to control fluid flow, said valve comprising aplate having an annular series of valve ports and an opening within saidannular series, a cup-shaped housing mounted to said plate about saidopening and having a bottom opening aligned with the opening in theplate, said housing comprising a wall flaring radially outwardly fromsaid opening and convexly away from said plate to constitute aprogressively engageable diaphragm backing, a first annular diaphragmover said ports, said diaphragm having an inner periphery clampedbetween said wall and plate, said diaphragm having an outer peripherydisposed radially beyond said valve ports and free for movementrespecting said plate, said first diaphragm being yieldable away fromsaid plate under fluid pressure through said ports toward contact withsaid convexly flaring wall, said housing having a top of greater areathan its open bottom, a plate across said top provided with an annularseries of valve ports, a second annular diaphragm over said ports, and abutton clamping the center of said second diaphragm to said plate, saidbutton comprising a head constituting a backing for said seconddiaphragm.

4. The device of claim 3 in which said annular series of valve ports insaid plates are arranged in angularly spaced groups of apertures, saidplates comprising radial spokes between said groups, said diaphragmsbeing provided with radial outwardly opening slits aligned with saidspokes.

References Cited in the file of this patent UNITED STATES PATENTS WilsonSept. 29, 1868 Meister June 27, 1916 Shartle Mar. 23, 1920 Le ValleyJuly 5, 1927 Barks Apr. 21, 1931 Mosel Mar. 25, 1941 Groeniger June 22,1943 Douglas Jan. 1, 1952 FOREIGN PATENTS Great Britain Feb. 8, 1861Norway June 19, 1899

